The bottle blowing process is a two-way stretching (longitudinal and transverse) process. During this process, the PET chains extend, orient and arrange in two directions, thereby increasing the mechanical properties of the bottle wall and improving the tensile, tensile and impact resistance. strength and good air tightness. Although stretching helps to increase strength, it cannot be over-stretched. The stretch-blow ratio must be controlled: the radial direction should not exceed 3.5~4.2, and the axial direction should not exceed 2.8~3.1. The wall thickness of the preform should not exceed 4.5mm. .
Blowing is performed between the glass transition temperature and the crystallization temperature, which is generally controlled between 90 and 120 degrees. In this range, PET behaves in a highly elastic state and becomes a transparent bottle after rapid blow molding and cooling. In the one-step method, this temperature is determined by the length of cooling time during the injection molding process (such as Aoki bottle blowing machine), so the relationship between the injection and blowing stations must be well connected.
The blow molding process includes: stretching - one blow - two blows. The three actions take a very short time, but they must be coordinated well, especially the first two steps determine the overall distribution of the material and the quality of the bottle blowing. Therefore, it is necessary to adjust: stretching starting timing, stretching speed, pre-blowing starting and ending timing, pre-blowing pressure, pre-blowing air flow, etc. If possible, it is best to control the overall temperature distribution of the preform. The temperature gradient between the inner and outer walls of the billet.
HUATAO provides blow molding equipment. Including:
Plastic Mold Equipment
Automatic Blow Molding Machine
Semi-automatic Blow Molding Machine
PS Foaming Machine
EPE Foaming Machine
PU Foaming Molded Machine
Horizontal lnjection Molding Machine
vertical lnjection Molding Machine
All-electric Injection Molding Machine
Thick Sheet Blister Machine
Thin Sheet Blister Machine
Color Plastic Masterbatch
Plastic Recycle Machine
Whether you need help with equipment selection, process optimization, or design customization, our team can help. We have the expertise and knowledge to analyze your project needs, identify challenges and develop innovative solutions.